Pour point depressant for lubricating oils



Patented Dec. 22, 1942 UNITED STATES PATENT OFFICE POUR POINT F03 LUBRIOAT- v I Y Jacob Faust, Belleville, N. 1., assirnor to L. Sonneborn Sons, Inc. a corporation of Delaware Application December 31, 1940, Serial No. 872.485

iciaim. (01. 252-35) This invention relates to new and useful improvements in pour point depressants for lubricating oils.

Pour point depressants have in the past been used in connection with waxy petroleum hydrocarbon oils having a relatively high pour point one to the was contained therein. The use of.

these depressants, however, is attended by the disadvantage that the pour point obtained though in many. cases materially depressed. is substantially fugitive and reverts upon storage or in service progressively towards the pour point of the ori undepressed oil. 7

i have discovered that this disadvantage may be overcome and that a substantially permanent lowering of the pour point and a substantially non=iugitive, non-reverting pour point may beohtained by axis with the oil tin stearate.

For the a 1 of depressing the pour point off a para base oil, such as a Pennsylvania grade oil, in accordance with the invention, so much tin stearate is added thereto as is sufheient to appreciably reduce the pom point of the oil and preferably reduce the same at least l below its normal pour point. 0.01 to 1.0% will give satisfactory results in most cases. 3.2% tin stearate constitutes usually the maxinium amcunt in: the procurement oi maximum ll fil nw A ove ll.2 the depression obtained:

by the stearate will progressively decrease until it approaehes the value of 0.01% addition at about 13%. Thepreierred amount within the specified range is 9.2% tin stearate, which will yield maxim depression.

Though satisfactery depression is obtained within the bread ranges of bill to 1.6% oi tin etearate, net all additions wi that range will we satisfactory stable nonnverting pour points.

E have discovered that when using less than substantially ill and in excess of substantially tin stearate, the primary pourpointe obr in the all will hit a tendency to re vest and is oi a substantially fugitive character. When, however, tins tin stearate additions ts the ill to 0.75% range, substantially stable non fugitive and non-reverting points are proin the ioliog table various tin stearate concentrations in a Pelvania grade S. A. E. oil are illustrated reciting in the respective colconcentration of stearste; prim y P .stearate to be incorporated in a given-Pennpoint, the absolute reduction obtained, and the secondary pour-point measured in accordance with reversion tests:

showed appreciable depression, i. e., at least 10 from the original pour point of the oil plus 30 F. In concentrations below 0.1% and above 0.75% the pour point was substantially stable, whereas above and below these concentrations the same was fugitive. The pour point measurements were carried out as by the, A. S. T. M. tests for thecleterinination of pour point designated as 1397-39.

The reversion data cited in the table were obtained by storing the oil at 32 F. for 168 hours and observing the temperature at which the oilloses fluidity. I K

in the following Table H aseries of pour point reversion tests are tabulated for a variety of Pennsylvania grade oils: 1

Table II v Penn. grade oil (original Concentration Primary Secondary Raven pour tin atesmte pour point pour point sion point- I 25 F.)

n. F. SAE 10 0.2%tinstearate-..- -20 20l-15 0 SAE 20 fin i5 -15[-10 0 BAE 80..-- 5 --B/0 0 SAE mm- 0.25 otinsteamte.-. i0 0 SAE 4-0..-- 0.2 tinsikiamtenn 0/-5 01-5 0 BAE 4 0.25 tinstearate-.. v-5l-910 6 0 For best results it is essential that the tin' sylvania grade oil in accordance with the invention is one which willyield substantially clear solutions in the oil. Ii a product is used which does not satisfactorily form substantially clear solutions in the oil to be depressed, its efliciency, both as to reduction of pour point and as pour point reversion tendency will be found impaired, if not altogether 0. This is particularly'true 5B or products 'durins the manufacture or which oxidative or other detrimental influences have been permitted to disturb or negative therefor instance, with ammonia from aqueous stannous salt solutions preferably in an inert atmos- J phere such as CO2) with stearic acid at approxil0 mately 340 F. in substantially stoichiometrical proportions (calculated on Sn (stearateh). The reaction should preferably be carried out 1 in an inert atmosphere such as an atmosphere of CO: or the like.

The foregoing description is by way of illustration and not of limitation and I am not to be limited to any details but only by the appended claim in which I have endeavored to' claim broad- 1y all inherent novelty.

I claim: A lubricating oil composition of relatively low,

non-fugitive, non-reverting pour point comprising a wax-containing petroleum hydrocarbon oil having normally a relatively high pour point due to them contained therein,

and (Ll to 0.75% of a stannous stearate obtained by fusing together freshly precipitated stannous hydroxide with stearic acid in an inert atmosphere, sai'd stannous stearate being substantially soluble in said-hydrocarbon oil to form substai.

18 tially clear solutions -therein.

JACOB PAUBT. 

